Closure of bags and the like

ABSTRACT

A closure is provided for a plastics bag or pouch, especially for holding powdered materials, comprising two opposing sets of projecting legs ( 12, 22 ), each of which is provided with external protrusions ( 14, 24 ) so that the respective legs interlock with each other when the two sets of legs are pressed together.

[0001] This invention relates generally to the closure of bags, pouches and the like. Conventionally, zipper strip material is used to close such products, using the interengagement of resealable male and female profiles on the respective surfaces of the packaging material to effect the closure.

[0002] One of the problems with the packaging of material in powder form especially is that the powder can invade the profiles, blocking the channels and making the bags difficult or impossible to close and/or seal.

[0003] It is an object of the present invention to provide a novel “zipper” which is particularly appropriate for use with the packaging of material which is in powder form and which avoids, or at least mitigates, the aforesaid problems.

[0004] In accordance with the present invention this is achieved by a closure for a plastics bag, pouch or the like, comprising first and second films of plastics material having respective first and second surfaces in opposing relationship, a first plurality of legs projecting from said first surface, and a second plurality of legs projecting from said second surface, wherein each leg is provided with surface protrusions which are arranged to interlock with protrusions of legs of the other plurality of legs when the surfaces are brought towards each other.

[0005] Also in accordance with the invention there is provided a bag or pouch of plastics material having a reclosable closure, the closure being provided on the inside of opposing surfaces of the bag or pouch and comprising a first plurality of legs projecting from one of said surfaces and a second plurality of legs projecting from the other of said surfaces, wherein each leg is provided with surface protrusions which are arranged to interlock with the protrusions of legs of the other plurality of legs when the bag or pouch is closed.

[0006] In one embodiment in accordance with the invention the legs are provided with randomly arranged protrusions and each leg tapers in the direction away from the root.

[0007] In order that the invention may be more fully understood, one embodiment of closure in accordance with the invention will now be described by way of example and with reference to the accompanying drawing which is a schematic illustration, in section, of the closure.

[0008] As shown in the drawing, the closure comprises a first film 10, which may be part of a bag, pouch or the like. Protruding from the surface of the film 10 are a plurality of legs 12, each of which is of narrowing cross-section in the direction away from the root of the leg where it meets the film. Each leg 12 is provided with a plurality of external protrusions 14 which are preferably randomly arranged on the surface of the legs. Alternatively, the protrusions may be provided in an ordered manner.

[0009] Set opposite the first film 10 is a second film 20 which likewise carries a plurality of projecting legs 22 having external protrusions 24. In the illustrated embodiment, each film 10, 20 is provided with three legs. As will be seen from the drawing, the legs are positioned for interengagement as the two films 10, 20 are brought together. As can also be seen from the drawing, each leg is faced with a narrowing channel as it moves deeper in between the legs of the opposing film. When the legs of the respective films are pushed sufficiently deeply into one another, the protrusions will engage one with another and lock the two films together. It will be appreciated that the action of this closure is not strictly that of a real zipper, but is more in the nature of a locking action which does nevertheless serve to effect retention of the product within the bag or package which is part of or which is secured to the films 10 and 20 .

[0010] The films and legs can be made of any suitable materials and the respective parts of the closure can be snapped or squeezed into engagement. It will be appreciated that when this closure is used for the retention of powders in an associated bag or pouch, any powder which invades the closure, i.e. which becomes located within the zone of the legs, can easily be shaken free or alternatively will not prevent interengagement of the closure elements and will not prevent an adequate closure or sealing of the package.

[0011] An important feature of the invention is that the individual legs are thicker at the root than in their outwardly projecting portions so that there is a taper. This enables the legs to locate more easily between one another, it enables better locking of the protrusions, and it facilitates the escape of powder or other foreign material from within the zone of the closure.

[0012] The number, location, orientation and configuration of the protrusions on the individual legs is a matter of choice, depending upon particular circumstances. The closure can be regarded as a series of interlocking branches, forming a zipper “tree”. The protrusions 14, 24 may be formed as separate nodules arranged in an ordered or random manner along each leg. Alternatively, the protrusions 14, 24 may be circumferential ribs extending around each leg. Such ribs can be parallel to the plane of the associated film surface or set at an angle to this plane, to give a degree of randomness. 

1. A closure for a plastics bag, pouch or the like, comprising first and second films of plastics material having respective first and second surfaces in opposing relationship, a first plurality of legs projecting from said first surface, and a second plurality of legs projecting from said second surface, wherein each leg is provided with surface protrusions which are arranged to interlock with protrusions of legs of the other plurality of legs when the surfaces are brought towards each other.
 2. A closure as claimed in claim 1, wherein each leg is thickest at the root where it joins the film surface.
 3. A closure as claimed in claim 1 or 2, wherein each leg is of tapered reducing cross-section in the direction away from the root where it joins the film surface.
 4. A closure as claimed in any preceding claim, in which the protrusions are arranged randomly on the legs.
 5. A closure as claimed in any preceding claim, in which each film is provided with three legs.
 6. A closure as claimed in any preceding claim, in which the protrusions are formed as separate nodules on the legs.
 7. A closure as claimed in any of claims 1 to 5, in which the protrusions are formed as circumferential ribs on the legs.
 8. A bag or pouch of plastics material having a reclosable closure, the closure being provided on the inside of opposing surfaces of the bag or pouch and comprising a first plurality of legs projecting from one of said surfaces and a second plurality of legs projecting from the other of said surfaces, wherein each leg is provided with surface protrusions which are arranged to interlock with the protrusions of legs of the other plurality of legs when the bag or pouch is closed.
 9. A bag or pouch as claimed in claim 8, wherein each leg is thicker at its root than in its outwardly protecting portion.
 10. A bag or pouch as claimed in claim 8 or 9, wherein the legs are provided with randomly arranged protrusions. 